Earlier work suggests that the reinforcing value of brain stimulation reinforcement (BSR) is inversely related to the temporal uncertainty about its onset. This proposal is a request for funds to develop an uncertainty model of BSR and to investigate the generality of the above relationship as it applies to stimulus uncertainty and rapid extinction effect with BSR. One experiment is an investigation of a possible mechanism for the effect, i.e. that reduced uncertainty results in lowered brain-electrode impedance which in turn results in a greater charge of stimulation. The research is a multidisciplinary approach which combines methodologies and theoretical conceptualizations of physiological psychology, operant learning, classical conditioning, and information processing.